Automatic device for adjusting the tension of the fabric in finishing machines



A. c. SCHOLAERT Feb. 2, 1960 2,923,046

. AUTOMATIC DEVICE FOR ADJUSTING THE TENSION OF THE FABRIC IN FINISHING MACHINES 2 SheetSheet 1 Filed June 15, 1956 INVENTOILZ Albert cho/aert rs: @tIu /gw' I mrovuusss Feb. 2, 1960 A. c. SCHOLAERT AUTOMATIC DEVICE FOR ADJUSTING THE TENSION THE FABRIC IN FINISHING MACHINES 2 Sheets-Sheet 2 Fil ed June 15, 1956 INVENTOIL, Albert C. Scho/aert as dkawk /guu ATTO M1 Ens United States Patent() AUTOMATIC DEVICE FOR ADJUSTING THE TENSION OF THE FABRIC IN FINISHING MACHINES Albert C. Scholaert, Tourcoing, France Application June 15, 1956, Serial No. 591,600

Claims priority, application France June 23, 1955 6 Claims. (Cl. 2629) The present invention relates to finishing machines in which the fabric travels over a predetermined path between the entrance to and the exit from the machine.

As a rule, in such machines, the various rollers on which the fabric passes have a peripheral speed slightly increasing from the entrance roller to the exit roller, in order that the fabric be permanently subjected to a slight tension. In this manner, the guidance of the fabric over its path of travel is facilitated.

Now, this tension, as weak as it may be, may have drawbacks in some applications. It is precisely the case in nap-raising machines where the tension of the fabric at the exit from the raising drums is detrimental to the quality of the nap-raising operation.

The aim of this invention is to remove these drawbacks in machines such as nap-raising machines, for instance, by providing a disposition by virtue of which the fabric, at the exit from the raising drums, is not subjected to any tension other than that which is due to the weight of a predetermined length of fabric.

This result is obtained, according to the main feature of the invention, by the fact that, downstream of the zone of the machine where it is desired that the fabric in motion be not taut, for instance at the exit from a raising drum of a nap-raising machine, provision is made, on one hand, of a roller provided with means for adjusting the linear speed of the fabric which passes over decrease) of said length corresponds an increase (or a 1 decrease) of the linear feed speed of the fabric which passes over said roller and that, consequently, the length of fabric within said zone keeps substantially constant.

By virtue of this disposition, the fabric travels through a machine with perfect continuity and regularity and may pass through one or more predetermined zones of this machine without any tension.

The invention has also for its object embodiments having at least one of the following features:

(a) The means for adjusting the linear speed of the fabric which passes over the aforesaid roller are constituted by means for adjusting the rotational speed of said roller over which the fabric embraces an arc of substantially constant length.

(b) The means for adjusting the linear speed of the fabric which passes over the aforesaid roller are constituted by means enabling the length of the arc embraced by the fabric over said roller to be varied, in'order to vary the relative slip between the fabric and said roller.

(c) In the case indicated under (b), said roller may be given a peripheral speed lower than the travelling speed of the fabric determined by takeup means positioned downstream of said roller, so that the latter exerts upon the fabric a variable decelerating effort variable in response to the length of the arc enveloped by the fabric over said roller.

(d) The means responsive to the length of the fabric in its tension control zone are constituted by a member, such as a horizontal bar, which rests against the bottom of a loop formed by the fabric in said control zone, the weight of said member, preferably, being almost balanced in order that no additional tension be introduced in the fabric.

(e) The means responsive to the length of the fabric in its tension control zone are constituted by a vat, plate, or the like, arranged under the portion of the fabric which forms a loop and responsive to the weight of fabric of this loop which rests upon said plate or vat.

(f) The means responsive to the length of the loop are carried by an arm pivoted on a horizontal shaft and provided with a balancing counterweight.

(g) In the case indicated under (b), the means responsive to the length of the loop may be connected with the means for adjusting the linear speed of the fabric by a mechanical connection comprising a servomotor device, the power of which preferably is derived from the aforesaid roller.

(h) In the case indicated under (a), the means responsive to the length of the loop may be connected to a potentiometer belonging to an electronic device which is adapted to adjust the speed of an electric motor for driving the aforesaid roller.

Further objects and advantages of the invention will be apparent to those skilled in the art, from a consideration of the following description of some specific embodiments of the invention, shown by way of examples, in the accompanying drawings, in which:

Fig. 1 shows a side diagrammatical view of the essential part of a nap-raising machine with metallic rotary teazles, equipped with a device for adjusting the tension of the fabric at the exit from each of the two raising drums, said device comprising a bar which controls an electronic regulator, and

Fig. 2 represents, in perspective, a modification of the adjusting device of Fig. 1, in which a vat controls a mechanical regulating device.

Referring first to Fig. 1, a nap-raising machine comprises a frame 1 in which are mounted a first raising drum 2 and a second raising drum 3 of conventional design which it is useless to describe here. These drums are driven in unison, in opposite directions, from a common driving shaft 4 coupled with an electric motor 5.

The fabric 6 to be nap-raised enters the machine over an entrance roller 7, and then passes over a detour roller 8 and a feed roller 9 driven by an electric motor 11.

The motor 11 is, for instance, a DC. motor the speed of which may be adjusted by an electronic device 12 provided with a knob 13 for adjusting the speed of travel of the fabric which is proportional to the speed of the motor 11.

The fabric then passes on two detour rollers 14, 15, and on a system of two rollers 16, 17 carried by an arm 18 coaxial with the raising drum 2 and which makes it possible to vary, in a manner known per se, the length of the arc of contact of the fabric on said drum.

Upon leaving the first raising drum, the fabric forms a falling loop which passes under a regulation bar 21 supported, at both its ends, by two arms 22 rigid with a shaft 23 mounted for pivoting movement in the frame 1 of the machine. If it is desired, the weight of the regulation bar 21 may be partially balanced, by means, for instance, of a counterweight carried by an extension of the arm 22 beyond the shaft 23. The fabric moves back upwardly to a take-up roller 24 driven by an electric motor 25 also supplied through the medium of elements of the electronic device 12. Upon leaving the take-up roller 24, the fabric then passes through the second part of the machine which comprises the second raising drum 3. This second part is similarly designed and the fabric successively passes on the following members: detour rollers 27, 28, 29, raising drum 3, regulation bar 31, de tour rollers 32, 33, take-up roller 34 and thence, toward adevice for discharging the fabric (not shown). The take-up roller 34 is driven by an electric motor 35 the speed of which also is controlled by elements of the electronic device 12, as will be seen hereinunder.

On the shaft 23 which carries the first regulating bar 21 is secured a toothed sector 37 in mesh with a toothed pinion 38 rigid with the shaft of a potentiometer (not shown) electrically connected to the electronic device 12. The arrangement of the assembly is such that, when the shaft 23 pivots clockwise (looking at Fig. 1, it drives the toothed sector 37 and, therefore, the aforesaid potentiometer in the direction which, through the medium of the electronic device 12, causes the speed of the motor 25 of the take-up roller 24 to decrease. Conversely, if the shaft 23 pivots in the reverse direction, it causes the rotational speed of said take-up roller to increase.

The regulation bar 31 similarly acts, through the medium of another potentiometer device, upon the speed of the motor 35 for driving the take-up roller 34.

The operation of the device which has just been described is the following:

Assuming the machine is in operation, it will be seen that the fabric travels through the machine and passes around both raising drums. The adjustment of every member, including those of the electronic device, is such that the peripheral speeds of the feed roller 9 and of the take-up rollers 24 and 34 are the same. If it is desired to modify the speed of progression of the fabric through the machine, the adjusting knob 13 is acted upon and the speeds of the three aforesaid rollers vary by the same amount. The fabric, therefore, circulates at a uniform speed throughout the machine.

The fabric forms a loop at the exit from each of both raising drums, so that it is practically not taut at these places, a condition which is favorable to a high napraising efficiency.

If, for any reason, the length of the loop of fabric at the exit from the first raising drum 2, for instance, decreases by a certain amount, the regulation bar 21 rises and drives the arms 22 with it, which, as hereinabove explained, causes the speed of the take-up roller 24 to decrease. This results into a lengthening of the loop which reassumes its original length while leaving the regulation bar to come back to its original position.

Conversely, a lengthening of the loop would cause the speed of the take-up roller 24 to increase.

It will be seen, therefore, that the loop of fabric keeps a length which varies little, by virtue of the action of the regulating device provided for this purpose.

The same is true, of course, of the length of the fabric loop which is positioned at the exit from the second raising drum 3, under the action of the regulation bar 31 which acts upon the speed of the take-up roller 34.

In order that this device always operates correctly, there is provided, for the take-up roller 34, a regulation area (over approximately for instance, of the steady rate speed) wider than that of the take-up roller 24 (for instance approximately 10% of said speed).

Referring now to Fig. 2, description will be given of a modification which differs from the embodiment hereinabove described in that the regulation bar is replaced by a vat which weighs the Weight of the excess of the loop and in that the take-up speed of the fabric is regulated by means of a device which varies the length of the arc embraced by the fabric over a roller placed downstream of the loop, the transmission not being effected by electronic means, but rather by mechanical means.

Fig. 2 shows only the portion of the regulating device which cooperates with the first raising drum 2, it being understood that provision is made for an identical device adapted to cooperate with the second, raising drum 3.

In this Fig. 2, are again seen the fabric 6 which passes on-the rollers 14,15, 16, 17 and the drum 2, then falls down into loop formation and travels upwardly to two adjusting rollers 41, 42 and a decelerating roller 43. Thence, the fabric travels again downwardly and passes on detour rollers 27, 28 as in the embodiment of Fig. l.

The end of the loop of fabric is supported by a vat 45 in which it rests in a few plies. This vat is supported, at both ends, by two levers 46 (only one of which is visible in the drawing) rigid with a shaft 47 journalled in the frame of the machine. The lever 46 is formed with an extension 48 on which is adjustably secured a counterweight 49. The latter is so positioned on the extension 48 that the restoring torque exerted by this counterweight be somewhat in excess of the torque created by the weight of the vat 45.

The rising and falling movements of the vat 45 in response to the variations in the length and, consequently, in the weight on the fabric loop, serve for ensuring the displacement of both rollers 41, 42 through a mechanical transmission which will be described hereinunder. Both these rollers 41, 42 are supported, at each of their ends, by a flange 51 adapted to pivot on the shaft 52 of the decelerating roller 43 and rigid with a worm-wheel 53. The fabric, which rests simultaneously on both rollers 41, 42 and on the decelerating roller 43, embraces over the latter an arc of longer or shorter length, according to the angular position of the flanges 51 on the axis of the shaft 52.

The mechanical connection between the flange 51 and the lever 46 comprises a rod 55 articulated to another rod 56 rigid with a fork 57 secured to a shaft 58 which is journalled in the machine frame. The fork 57 serves for coupling a slider 59 selectively with either one or the other of two pinions 61, 62 loosely mounted on a shaft 60 which is rigid with the slider 59. Both pinions 61, 62 are rotatively driven in opposite directions from two pinions 63, 64 having oppositely inclined helical teeth and rigid with a shaft 52 which loosely supports the decelerating roller 43. The pinion 61 is operatively connected with the pinion 63 through the medium of two pinions 65, 66, whereas the pinion 62 is connected with the pinion 64 through the medium of two further pinions 67, 68. Finally, the rotational movements of the shaft 60 are transmitted to the worm-wheel 53 through a couple of helical toothed wheels 71, 72 and a worm 73 in mesh with the wheel 53.

Furthermore, at a level definitely higher than that of the vat 45, a bar 74, fixedly positioned in vertical direction, which extends through the loop of fabric and prevents the latter from rising too high, for instance at the moment when the machine is set in operation, should the operator let the fabric acquire too heavy an initial tension. As soon as the machine is operating, the bottom of the loop reassumes its normal position, as will now be seen.

Assuming the machine is in normal operation, the lever 46 is substantially in horizontal position under the action of the light excess of length of the loop of fabric supported by the vat 45. The rollers 41, 42 assume, with respect to the decelerating roller 43, a certain position which affords the fabric a contact over a certain are on said roller. The peripheral speed of the decelerating roller 43 is slower than the travelling speed of the fabric, so that the latter is all the more decelerated that it embraces a longer are over this roller. When the system is in steady operation, the slider 59 is stationary, in neutral position midway between the two pinions 61, 62.

If, for any reason, the loop of fabric increases in length, the excess of weight of this loop causes the vat 45 to descend, the lever 46 rocks, the rods 55 and 56 are lowered, the fork 57 oscillates and shifts the slider 59 into mesh with the toothed wheel 62, the shaft 60, therefore, is rotatively driven and in its turn drives the wheels71, 72, the worm73 and the wheel 53 in the direction which causes both rollers 41, 42 to rise. The fabric embraces a shorter are over the decelerating roller 43; it is, therefore, decelerated to a lesser extent, and the loop is reabsorbed to such an extent that its weight is sufficiently decreased for letting the lever 46 reassume the horizontal position. At this moment, the slider 59 again is disconnected.

Conversely, if the loop of fabric shortens, the vat 45 rises and couples the slider 59 with the pinion 61 which rotates in the reverse direction with respect to that of the pinion 62, so that the rollers 41, 42 move downwardly. The are embraced by the fabric over the decelerating roller 43 increases, and the fabric, which is more strongly decelerated, progresses not so fast until the position of equilibrium of the vat 45 is restored. In practice, this position of equilibrium is obtained after a few oscillations of the system.

Of course, the invention is not limited to the embodiments described and represented which have been given merely by way of examples, many modifications thereof may be made, according to the applications contemplated, without departing thereby from the scope of the invention.

Thus, in the electronic control device of Fig. 1, the devices with regulation bars 21, 31, might be replaced by devices with a vat such as that of Fig. 2, and, conversely, the vat device of Fig. 2 could be replaced by a device with a bar.

In the device of Fig. 2, a mechanical control of a type other than that described and represented and even a control which is not a mechanical control might also be utilized.

Furthermore, the variations in the speed of the take-up rollers of the installation of Fig. 1 could be controlled mechanically or hydraulically, instead of being controlled electronically.

Finally, any other disposition for adjusting the travelling speed of the fabric might be adopted for keeping a loop of substantially constant length as hereinabove explained.

What I claim is:

1. In combination with a nap-raising machine having at least one nap-raising drum having a feed side and an exit side, a roller located on the feed side of said drum for feeding a fabric to said drum, another roller located on the exit side of said drum and receiving said fabric, said fabric forming a loop between said drum and said other roller, and loop-engaging means responsive to the level of the bottom of said loop; a device for varying the speed of said fabric while it is in engagement with said other roller, and means cooperating with said loopengaging means and actuated by the variation in the size of said loop for actuating said device to thereby maintain a loop of constant length.

2. A device in accordance with claim 1, wherein said device for varying the speed of said fabric consists of a device varying the speed of said other roller.

3. A device in accordance with claim 1, wherein said device for varying the speed of said fabric consists of a device varying the arc of the fabric engaging said other roller.

4. In combination with a nap-raising machine having at least one nap-raising drum having a feed side and an exit side, a roller located on the feed side of said drum for feeding a fabric to said drum, a take-up roller located on the exit side of said drum and receiving said fabric, said fabric forming a loop between said drum and said take-up roller, and a regulation bar engaging the curved portion of said loop and pressing against said curved portion; an electronic device for varying the speed of said take-up roller, and means operatively connecting said regulation bar with said electronic device for actuating said device to thereby maintain a loop of constant length.

5. In combination with a nap-raising machine having at least one nap-raising drum having a feed side and an exit side, a roller located on the feed side of said drum for feeding a fabric to said drum, a decelerizing roller located on the exit side of said drum and receiving said fabric, said fabric forming a loop between said drum and said decelerizing roller, a vat engaging the curved portion of said loop and pressing against said curved portion, and means connected with said vat for adjustably maintaining the level of said vat depending upon the amount of the vat-engaging portion of said fabric; a swingable flange connected with said decelerizing roller, rollers carried by said flange and engaging said fabric adjacent to said decelerizing roller, means connected with said flange for turning said flange in opposite directions to vary the arc of the fabric engaging said decelerizing roller, whereby the speed of said fabric is varied, and means operatively connecting said vat with the lastmentioned means for actuating the last-mentioned means to thereby maintain a loop of constant length.

6. In combination with a nap-raising machine having at least one nap-raising drum, a roller feeding a fabric to said nap-raising drum, a take-up roller spaced from said drum, said fabric forming a loop between said drum and said take-up roller and a regulation bar engaging the curved portion of said loop and pressing against said curved portion; a pivoting shaft, at least one arm movable with said shaft and connected with said regulation bar, a toothed sector movable with said shaft, a toothed pinion meshing with said sector, an electronic device for varying the speed of said other roller, and means operatively connecting said pinion with said electronic device.

References Cited in the file of this patent UNITED STATES PATENTS 1,916,467 Eger July 4, 1933 2,166,551 Perry July 18, 1939 2,214,609 Drake Sept. 10, 1940 2,278,136 Otis et a1 Mar. 31, 1942 2,517,861 Franklin Aug. 8, 1950 2,737,089 Baumgartner Mar. 6, 1956 

